Refrigerator



April 5, 1932 T H FM N 1,852,707

REFRIGERATOR Filed May 15, 1950 s Sheets-Sheet 1 gmenliov Apr 1932- c. T. HOFFMAN REFRIGERATOR 3 Sheets-Sheet 2 Filed May 15, 1950 REFRIGERAT/NG A PPA RATUS to DEFROS IN Y gwuentoo To 004 5UPPLY.

Eff "um/1 April 5, 1932. c HOFFMAN v 1,852,707

REFRIGERATOR Filed May 15, 1930 3 Sheets-Sheet 3 Patented Apr. 5, 1932 UNITED STATES PATENT OFFICE CHARLES T. HOFFMAN, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR OF ONE- HALF TO EMORY L. GEOFF, OF WASHINGTON, DISTRICT OF COLUMBIA.

REFRIGERATOR Application filed May 15, 1930. Serial No. 452,687.

is proposed to utilize a visual indicator in .the form of alamp for indicating the defrosting cycle or period. In the present construction it isproposed to utilize this lamp not only for the purpose just stated but also to illuminate the interior of the box upon the opening of the refrigerator door. In that connection it is proposed so to locate thelamp that it is entirely concealed within a wall of the cabinet but the lamp box is provided with windows or openings which not only render the illuminated lamp visible from the front of the box but also permits the lamp to amply illuminate the interior or food compartment of the box. This novel arrangement locates the lamp in such a way that it is entirely out-side of the food compartment and at the same .time all the wir-- ing connections leading thereto are embedded in a wall of the box thus not only preventing breakage of the lamp by the placing of .articles in the box but also rendering the electrical installation entirely safe.

Another object of the invention is to provide a novel switch mechanism which is actuated by electro-magnets supplied with current from a bell-ringer transformer, or the like, which may be connectedwith a standard 110 volt source of supply while at the same time permitting the reduced voltage used in the magnets to be utilized in the push-button circuit through which the owner of the box initiates the defrosting period/ A feature of the switch mechanism shown and described herein is that the swinging movement of one of the oscillating switch arms is temporarily arrested in a part of its movement thereby to prevent the locking of the motor off in 7 event the push-button circuit is closed by mistake or design while the .ferred With the above and other objects in View which will more readily appear as the naturecircuit of the thermostat on the coils' or coil baflles is closed. In other words, thepresent switch has a'delayed movement which effectually prevents the condition above reof the invention is better understood, the same consists in the novel construction hereinafter more fully described, illustrated, and claimed. V

A preferred and practical embodiment of the invention is shown in the accompanying drawings, in which;

Fig. 1 is a front'elevation of a portion of an icebox illustrating the lamp feature of the invention.

Fig. 2 is a vertical cross-sectional view taken on the line 22 of Fig. 1.

Fig. 3 is a detail cross-sectional on the line 33 of Fig. 1.

Fig. 4 is a detail sectional view of the door switch. v

Fig. 5 is a diagrammatic view illustrating the combination of the push-button switch, defrosting lamp, door control switch, thermostat switch, and automatic switch device operating with both high and low voltage currents.

Fig. 6 is a plan view of the complete automatic switch.

Fig. 6a is a detail top plan mercury container carried by the movable switch arm.

'ew taken Fig. (ibis a detail view illustrating more fully the delayed action feature of the switch.

view of the Fig. 7 is adetail vertical sectional view taken on the 1ine 7-7 of Fig. 6.

Fig. 7a is a detail view illustrating the application of a non-tilting mercury container to the movable switch ar Similar reference characters designate corresponding parts throughout. the several views.

Referring to Fig. 1 the cabinet or icebox is designated generally as A, the same being of the usual type now generallyon the market and having the door Bfor closing and permitting access to the compartment which houses the evaporator and the food.

Above the door B there is preferably ar.

rangeda suitable face plate C having associated therewith a push-button D and a lens E; The lens E covers the front end of an opening or window F formed in the frame member F of the box which communicates with a lamp box G so that when the lamp H is illuminated the light therefrom will be visible through the lens. The said lamp box G is concealed within a wall of the box or cabinet A and is provided with an opening or window G which may be covered in any suitable manner by a glass orv other transparent element I located within the food compartment of the box and at the inside of the door B. Thus, the lamp H is intended to be illuminated during the defrosting period as will hereinafter appear. Also when the door B is opened, the closing of the door switch B will cause the lamp to be illuminated and the interior of the cabinet will be flooded with light, while at the same time the lens E W111 be illuminated.

The door switch B may be of any conventional type which breaks the circuit when the door B is closed and on the other hand closes the circuit when the door is open. The circuit connections for the lamp H are such that whenever the user of the box opens the door the interior of the box will be flooded with light, and even though the door is closed, when the defrosting period occurs the lamp will be illuminated by the closing of the circuit through the automatic switch designated generally as S (Fig. 5). Therefore, while the box is defrosting the user of the box Wlll. know the condition of the box through the illumination of the lens E even though the door is closed, and if the box is opened during the defrosting period the interior of the cabinet will still be flooded with light, the opening and closing of the door having no effect thereon.

Before proceeding to a description of the circuits involved in the present combination features, it may be pointed out that the pushbutton device D illustrated in detail in Fig. 3 may also be of any conventional and wellknown type on the market and therefore a detailed description thereof 1s unnecessary.

Referring now to Fig. 5 of the drawings, the various parts are shown in the defrosting position, that is, the position when the circuit to the motor of the refrigerating apparatus is broken and the lamp H is illuminated, thus rendering the door switch B inoperative since. the circuit is shunted therearound while the thermostat switch T on the evaporator is open. It may be pointed out that this latter switch remains open until the food compartment of the box warms up to the predetermined degree thereby to automatically close the circuit to the switch device S and throw the same to its other position to again close the circuit to the motor of the refrigerating apparatus.

The push-button D is connected by the wire (1 to the low voltage binding post R of the bell-ringer transformer U. The bell-ringer transformer U is connected to the volt current supply by the wires u and u. When the switch arm 2 is in the dotted line position shown in Fig. 5 the circait from the push-button D will he closed from the bind ing terminal R of the transformer through the transformer itself to the binding terminal R" thereof and thence through the wire m to the electro-magnet M which is connected by the wire m with the electro-magnet M, and thence through the wire 92 to the conductor 3 carried by the end of the switch arm 2 which is engaged with the contact 1. Thus the circuit is completed from the push-button through the electro-magnets MM which will cause the energization of the armature O and cause the movement of the link 4 connected therewith, which in turn will cause the movement of the arm 5 to which it is pivotally connected as indicated at 5a thereby to cause the movement of the head 6 carried by the arm to engage with the sliding dog 7 and move the switch arm 2 to the full line position shown in Fig. 5. The switch S is then in the defrosting position as indicated by the legend on the drawings.

When the switch S is in the so-called defrosting position the lamp H will be illuminated, and the circuit which causes the illumination of the lamp will now be traced.

Starting with the current supplied by the 110 volt source, the same passes over the line u to the conductor 8 which is connected with the inside terminals 9 of a tilting mercury tube 10 which is carried by the actuating arm 11. The actuating arm 11 and the switch arm 2 are pivoted on the common axis 12 and are held in the position to which they are thrown by the action of the member 6-and dogs 7 and 7a by the tensioning spring 13.

When the mercury tube 10 is tilted to the position shown in Fig. 5 the mercury 14 in the tube closes the circuit between one of the inside terminals 9 and the outside terminal 9a. This terminal 9a is connected by the wire 15 with one of the terminals of the lamp H and after the current passes through the lamp it returns to the 110 volt line a over the wire 16. As long as the defrosting cycle continues the circuit will be closed through the lamp H in the manner just described, and it will, of course, be understood that the defrosting cycle continues until the circuit over the low voltage line is again closed by the thermostat switch T mounted on the evaporator.

Assuming that the frost or ice has completely left the coils and baflie plates of the evaporator and. the box has warmed up to the predetermined temperature, the thermostat switch T automatically closes the cir-' cuit through the electro-magnets M.-M- to, again cause the actuation of the armature O;

and cause the head 6 to engage with the dog The circuit will now e traced from the thermostat switch T through the'switch S. Immediately upon the engagementvof the contacts t and t of the'thermostat switch T I the low .voltage circuit will be closed from the contact at over the line 17 which is connected with the contact 1a of the switch S. Fromthence the current will pass through the conductor 3 over the line n to the electro-magnet' M which is included in circuit with the electro-magnet M as previously described, and the latter'in turn is connected with the bell-ringer transformer U at the terminal R. The other terminal R of the. bell-ringer transformer is connected with the line d which has connected thereto at any suitable point the wire 18 leading to the contact if of the thermostat T. When the circuit is thus completed the armature O actuates the shaft 5 and causes thehead 6 to engage the dog 7, thus moving the arm 2 to the dotted line position and returning switch contacts 1 and '3 into engagement and also tilting the mercury tube-JT to the position opposite to that shown in Fig. 5 thereby to-throw the mercury 14.- to the other'e'nd of the tube to thus close the circuit between the right-hand inside contact 9 and contact 9b. The contact "911 is connected by the wire 19 to the motor defrosting cycle the door controlled switchof the refrigerating apparatus, and the latter 7 is connectedby the wire 20 with the line a of the 110 volt current supply. In that way the circuit is closed to the motor of the refrigerating apparatusand the refrigerator assumes the refrigerating cycle, the usual the 110 volt line a, and its other terminal b is connected by the wire 22 with one of the terminals of the lamp H. The other terminal of the lamp is connected with the wire 16 v which isthe return wire line for the lamp circuit which is commonv to both the defrostingc ircuit and the door controlled circuit for the lamp. It is pointed out that the wire 15 of the defrosting circuit is connected to the wire 22 in such a way that when the circuit is closed through the switch S on the contacts are'shunted. Therefore, when the 'door is closed the lamp 'will'remain illuminated to indicate the defrosting cycle through the lens E but ifthe door B should be opened the closing of the switch B will have no elfect on the lamp. This is an important and essential feature of the arrangement described which enables .the use of a common source of light for indicating the defrosting cycle as well as illuminating the interior and contents ofthe box.

Having now set forth the general operation of the various units,.the important and distinctive feature. of the delayed action operation of the switch S will be described.

As soon as the contacts t and t of the thermostat '1 are closed the switch arm 2 is thrown from the full line position shown in Fig. 5 to the dotted line osition. The thermostat switch is necessari y more or less slow acting since it is controlled by box temperature warming up to close thecontacts and the lowering temperature of the evaporator coils after the refrigerating cycle is again started to open the contacts. Thus, there are a few minutes after the motor has been switched on again, after the defrosting period has ceased and the light H extinguished, that the contacts t and t are still in engagement.

Now if by accident or design the push button Dis pressed whilethe said contacts t and t are in engagement, such closing of these contacts will have no damaging effect on the switch or the motor of the refrigerating apparatus. That is to say, under no circumstances can the motor of the refrigerating apparatus be locked in an inoperative position due to switch arm 2 again being thrown back to the full line or defrosting position shown in Fig. 5, which position it has just left due to the closing of the contacts t and t'..

stat are still engaged, and the push-botton D is pressed or held in, the electro-magnets M and M will, of course, be energized by the 1. lil

closing of the push-button circuit. The

spring controlled armature 0 being actuated by the magnets will cause the plunger 5-6 to pull the dog 7 a and throw the arm 11 over against the'tension of the spring 13 which pulls arm 2 back partially toward the full line position where it remains temporarily until the plunger 5-6 moves back to its full return stroke, permitting dog 7 to drop off the front edge of the plunger member 6 thereby premitting conductor 3 and contact 1a to engage. These contacts are still alive under this condition due to the contacts t thermostat T this action will be repeated with the other dog 7 a. In this way the armature 0 functions substantially as a motor operating to alternately throw the arm 11, and consequently the arm 2, first toward the contact 1a and then toward the contact 1 until the push-button is released, whereupon the switch lands in the motor on position. In other words, so long as the thermostat contacts t and t remain closed the effect of the energization of-the magnets M and M will be to throw the switch arm 2 to the motor on or dotted line position shown in Fig. 5, and naturally as-soon as the circuit" scribed, will now be referred to more in detail.

As previously indicated, the switch arm 2 and its companion switch arm 11, which carry the mercury tube 10 are mounted on a common axis 12. The arm 2 is provided with suitable guides for receiving the shanks of the dogs 7 and 7a, and the said shanks of the dogs are provided with the offset projections 71) for engaging with the switch arm 11 as the heads of the dogs are alternately engaged by head 6 of the plunger. The arms 2 and 11 are connected by the tension spring 13 in such a way that when the conductor 3 of the switch arm 2 is held against either contact 1 or 111, the upper end of the arm 11 is engaged with one of the stops 11a, which stops limit the movement of said arm 11; lVhen the armature O is moved against the tension of its spring 0 by the energization of the magnets M and M, thereby to move the plunger 5-6, the head 6 of the plunger will first engage, for example, the head of the dog 7 which lies in its path of movement as shown in Fig. 5. The movement of the shaft 5 of the plunger will pull the dog 7 through its guide on arm 2 and cause the offset portion 76 of the dog 7 to engage the arm 11 and move it against the tension of the spring 13. When the arm 11 has moved sufiiciently to cause the spring 13 to pass the center of the axis 12, the energy of said spring will snap the switch arm 2 away from the contact 1a, thus elevating the dog 7 and causing it to clear the end of the plunger head 6 with which it has been engaged. The head of the dog 7 a will then be thrown on to the relatively long edge 6a of the plunger head where it will remain temporarily and likewise temporarily hold the switch arm 2 away from its receiving contact 1, thereby permitting the plunger 5 to fully return to its normal position under the influence of the spring tensioned armature O.

\Vhen the plunger 5-6 nearly reaches the turn of the conductor 3 toward its receivingcontact is temporarily delayed, thereby permitting the plunger to get back to the original position from which pulled, its return being effected by the spring 0 upon the openin g of the contacts to the magnets.

The same action just described in connection with the head 6 of the plunger and thedog 7 will occur in relation to the head 6 of the plunger and the dog 7a on the next movement of the armature 0. Thus, it will be observed, that the elongated 6a of the lunger performs two important functions. irst, it lets the plunger get back to its original position upon the opening of the circuit to the electro-magnets by permittin the spring 0 to force the plunger back to its original position; and, second, this delayed action holds the conductor 3 away from its receiving contact temporarily until the plunger is in position to engage the proper dog necessary for actuation of the switch in the opposite direction to that which it has just left.

\Vhile the switch mechanism S has been described and shown in connection with low voltage on the contacts 1-1a and conductor 3. which are included in the push-buttonthermostat switch circuits, nevertheless it will, of course, be understood that this switch mechanism may be utilized when and where desirable to handle commercial voltages, and particularly so adapted because of the quick action of the arm 2. Therefore, it will be apparent that the magnets M and M and the armature shown in the embodiment of the invention in Figs. 5 and 6 merely serve as an actuator for the plunger 5-6, and the necessary changes in the actuator to adapt it to also handlecommercial voltages are well within the skill of anyone versed in the art.

In the embodiment of the switch device S shown in Fig. 6 precisely the same elements previously described in connection with Fig. 5 are used. However, for the purpose of illustrating the adaptability of this switch to a commercial form all of the various switch parts are shown as being mounted on a base 25 which may also serve to conveniently carry the binding post blocks 26 and 27. The block 26 carries the terminals for the low voltage connections and block 27 carries the terminals for the high voltage connections, all of which are marked in accordance with the end of its movement due to the spring 0 pulldiagram, Fig. 5. The entire mechanism car ried b the base maybe placed within a suitab e metal box or case 28 having the knockout openings indicated at 29 in the conventional manner. While the cover is not shown for the box 28, it, of course, may be provided with such cover in accordance with standard practice. a

A further'novel and distinctive feature of the present invention is shown in Fig. 7a. In this fi glass isc-like container- '30 for containing mercury or other conductive fluid and havin associated therewith the terminals 31, 32, an 33. The container 30 may be mounted in any suitable manner on the arm 11 as, for ex-' ample, through the medium of the bracket 34, which is carried by the arm 11 in such a way that as the arm is shifted from one posi- .tion to another the glass or other insulated 2 container will move but the mercury will direction.

- 1. In a refrigerator cabinet, the combinamaintain a relatively constant position. In other words, when the arm 11 moves the contacts 31 and 32 carried b the container will be shifted into and out 0 the mercury, while the contact 33 remains immersed therein. In the illustration given, the contacts 31 and 33 would be used for closing the circuit to the lamp H, while the contacts 32 and 33 would be used-to close the circuit to the motor of the refrigerating apparatus. The advantage of the use of this type of shiftable contactor is that it requires less energy to move the switch arm, since the mercury is not shifted as in the tiltable type mercury tube, nor is there any inertia to overcome as in the elongated tube type of conductor due to the mercurybeingheld at one end of the tube until the tube itself is tilted in the opposite I tion with the food compartment having a wall, a lamp compartment formed in said wall and having windows respectivel opening at the outside of the cabinet and into the food compartment, a lamp insaid lamp compartment, a switch for controlling the illumination of the lamp, and manually operated means for initiating the operation of said switch.

2. In a refrigerator cabinet, the combinetion with the food compartment having "a opening respectively at the outside of the cabinet and into the food compartment, av

lamp arranged in illuminating relation to said windows, an automatic'door controlled switch, and an automatic defrosting switch, both of said. switches being included in cir: cuit with the lamp.

3. In a. refrigerator cabinet having'a fgofd compartment, a door, an evaporatorloatedin .said compartment, and a motorfor ,cir-

'culating refri erant in the evaporator ;"*'thecombination 0 a lamp housed within, a wall re the arm 11 is shown'carrying a means controlled b of the food compartment, means in said wall of the food compartment for permitting the lamp to illuminate the food compartment,

means for rendering the lamp visible'from the outside of the cabinet, a circuit including the lampand both manual and automatic means for controlling the circuit to the lamp and the motor, and door operated switch means also included incircuit with the lamp.

4. In a refrigerator ,cabinet having a food compartment, a door, an evaporator located in said compartment and a motor outside of said compartment for circulating refrigerant in the evaporator; a wall of the cabinet havin windows opening to the outside of the ca inet and at the inside into the-food compartment, a lamp arranged 'in illuminating relation to said windows, separate switch devices respectively adapted to be manually and automatically operated for controlling the circuit to the motorand the lamp and a door operated switch also included in cirdevice located 1n said current supply line anterior to the refrigeratingapparatus, thermal responsive means \for operating the switch to control the circuit, said switch comprising'a pair of switch arms pivoted about a common axis, a s ring connecting said arms,

electro-magnetica y operated means for opcrating one of said switch arms, and means for temporarily delaying the full'action of the other arm.

6. Means for automatically defrosting refrigerating units of refrigerators equipped with electrically operated means for circulating a refrigerant in the unit and means for maintaining said units within predetermined temperature limits, comprising the combination with the current suppl line to said electrically operated means, 0 a thermal responsive member associated with the refrigerating unit, a switch device in said door, of a wall of the cabinet having windows,

current supply line anterior to the refrigerating apparatus including a pair of pivoted sponsive e ement, switch, and electro-magnetic means being included in circuit, and said 'electro-magnetic means for temporarily delaying the full operation of one of said switch arms until the "electro-magnetically operated means returns thermal responsive switch associated with the evaporator, a manually operated switch, and an automatically operated switch including electro-magnetically operated means, a pair of pivoted spring connected switch arms, means carried by one of 'said arms adapted to be engaged by said electro-magnetically operated means whereb one of said arms is permitted to make its ull stroke while the other 10 is prevented from making its full stroke until said electro-magnetically operated means returns to its normal position.

8. A refrigerator cabinet having a food compartment provided with a door, said cabinet also having an opening providing a window, a lamp arranged in illuminatin relation to said food com artment and window, a door controlled swltch, and a defrosting switch, both of said switches being included in circuit with the lam In testimon whereo I aflix m signature.

C RLES T. HO FMAN. 

